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Chemistry Its a REVIEW See how YOU DO Slide 2 ELEMENT, COMPOUND, or NEITHER??? OXYGENSUGAR WATERAIR SULFURJELLOCARBON DIOXIDE KOOL AIDALCOHOLSODIUM NEONPROTEINWATER NITROGENSEAWATERSODIUM CHLORIDE AMMONIAICEGOLD DIAMONDCOALSTEEL IRONCARBONCOFFEE BREADHYDROGENVINEGAR HYDROCHLORIC ACIDURANIUMCARDBOARD State 2 or 3 ways to identify a substance as one of these three choices What are Physcial Properties of a Substance? Chemical Properties? Slide 3 Physical Properties Include DENSITYCOLORLUSTERFRACTURE CRYSTAL STRUCTURE MALLEABILITY DUCTILITY FREEZING (MELTING) POINT BOILING (CONDENSATION) POINT CONDUCTIVITYMAGNETIC PROPERTIES FLAMMABILITYand any other characteristic that could be used to identify that substance Chemical Properties Include The characteristic ways in which compounds/elements react when they come into contact with one another Slide 4 Phase Changes (Physical Changes!) LIQUID SOLIDGAS ? ? ? ? ? ? Slide 5 Phase Changes (Physical Changes!) LIQUID SOLIDGAS SUBLIMATION DEPOSITION MELTING FREEZING BOILING CONDENSATION Slide 6 TEMPERATURECTEMPERATUREC A B C D E Phase change diagram Can you model a) the molecular changes, b) potential and kinetic changes for each indicated time interval? TIME Slide 7 Element = one type of atom only Cu = copperBr 2 = bromine Hg = mercury I 2 = iodine Slide 8 What other categories are there? What is a mixture? Elements cannot be separated into anything simpler by human means only smaller particles with the same characteristics! Compounds and mixtures can be separated into simpler components. Mixtures show the characteristics of the substances that they containnot a new set of characteristicsthey are relatively easy to separate. Compounds show new characteristics, not those of the substances they containthey are generally harder to separate. Slide 9 Sodium Chloride - NaCl Copper Sulfate - CuSO 4 Compound = 2 or more types of atoms Slide 10 How is an atom different from a molecule?? Slide 11 Atom = smallest basic unit of any element Slide 12 isopropyl alcohol = C, H, and O atoms glucose = C, H, and O atoms Molecule = more than one atom, usually more than one type of atom Slide 13 Assemble each of these into one of three groups Neutralheavy (one atomic unit)protonnegative light (1/1800 atomic unit)positiveneutron Electron orbits the central regionneutron inside nucleus different for the isotope forms when these change, ions form Constant for an element heavy (one atomic unit ) Slide 14 Br 35 79.904 which element? # protons?? # neutrons?? Atomic number?? #electrons? Atomic mass? Mass number?? Slide 15 Periodic Table an organization of elements, based upon their characteristics Slide 16 How do they differ?? Compoundmixture Polar.non-polar Acidbase Physical change chemical change Slide 17 Polar molecules have charged regions; non-polar molecules do not Water = polar molecule Carbon Dioxide = non-polar molecule Slide 18 Chemical Change Or Physical Change?? Bread rises. Ice melts. Baking soda + vinegar fizzes. A raw egg is cooked. Instant coffee dissolves in water. Chocolate melts in a warm room Alcohol boils. Paint dries. A photosynthesizing plant produces sugar. Slide 19 Radioactive Elements In what way do they change? Slide 20 Radioactive elements give off radiation, which changes their elemental identity This process is called radioactive decay. Slide 21 Bonding Its all about electrons!! Practice with Periodic Table groups I through VIII Slide 22 Electron locations in the atom (model) 1.How many electrons does the neutral atom contain? 2.The first 1 or 2 are placed into Energy Level #1 3.Energy Level 2 holds up to 8 electrons. 4.Energy Level 3 holds up to 8 electrons. 5.Energy Level 4 hold up to 8 electronsetc. NOWKeep track of the electrons in the outer energy level! Where on the Periodic Table are the elements with 1 outer level electron? NUMBER OF VALENCE ELECTRONS = GROUP NUMBER! Rule #1: EVERY ATOM REACTS TO GET 8 VALENCE ELECTRONS Slide 23 IONIC BOND Lithium + Chlorine Li becomes +1 ion, Cl becomes -1 ion Slide 24 COVALENT BOND 4 HYDROGEN ATOMS + 1 CARBON ATOM = 1 METHANE MOLECULE (NO IONS ARE FORMED)